


Down, Down Below

by Aggression



Category: Transformers - All Media Types, Transformers Animated (2007)
Genre: Bath Sex, Kink Meme, M/M, Sensation Play, Sense Play, Size Difference, Sticky Sexual Interfacing
Language: English
Status: Completed
Published: 2015-09-22
Updated: 2015-09-22
Packaged: 2018-04-22 21:09:54
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,916
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4850645
Author URL: https://archiveofourown.org/users/Aggression/pseuds/Aggression
Summary: <blockquote class="userstuff">
              <p>Optimus Prime knew he shouldn't wander the tunnels underneath Iacon, but he had done it so many times before. It was just his luck that the one time he went alone would be the one time he went down far deeper than he had ever intended. Who would've known that there was other mecha down here?</p>
            </blockquote>





	Down, Down Below

**Author's Note:**

> A fill for this [prompt](http://tfanonkink.livejournal.com/3587.html?replyto=5832707) on the kink meme. Also an attempt to break some writer's block.
> 
> If you feel there's another tag I should added to this please let me know. Also, it's currently unedited. I will come back to properly edit this I just can't commit more time to this this week.
> 
> Feb 11/2016: A good edit of this fic has finally been done! If I've still missed something please let me know.

Optimus Prime was a fool.

He could hear his superiors berating him in his processor. First, that mess that lost Elita-1, and now here he was, stuck Primus knows where in the sprawls underneath Iacon. He _wished_ his officers could actually berate him, for that would mean he was back in the military complex; he would be back somewhere familiar.

Everything around him was far from familiar. The undercity of Iacon was dangerous, technically off limits. And though him and his friends had spent parts of their academy days galavanting the tunnels right underneath the surface, Optimus never knew of anyone ever reaching down this far.

Optimus wasn’t even sure how deep he was into the planet right now. He had been walking through the tunnels, a habit he had taken to when he wanted to be alone. He always walked the same route, pathways he had been taking since he was younger. It had been different this time. He hadn’t noticed anything different, but apparently the floor had changed. That was very evident the moment it crumbled beneath his pedes.

He really had no idea how far he had fallen. All he knew is that he had scrambled when he fell, reaching out and trying to claw at any hold he could have grabbed. There hadn’t been much of a chance to catch himself before rock and metal gave way to air, and as he fell through the open space of a cavern he could begin to understand the fear Elita must have felt when her borrowed grappling hooks had timed out.  

He landed with a _thump_ and a cloud of dust.

He had dents and nicks all over his plating. One of his headlights had broken when he landed. One of his legs struts was definitely out of alignment. He wasn’t sure if the shame he was feeling at his situation was worse than the pain or not. Either way he felt like slag.

Optimus stood, turning himself about to try and gain his bearings as he casted what little light he had around the cavern. Rock, metal, more rock, the ceiling high above him, but he couldn’t make out the hole he had fallen though.

There would be no help coming for him. Some of his friends might be able to guess where he had been, but Optimus had left for the tunnels in a mood, and he wasn’t sure if anyone had even noticed him leave the barracks.

His sensors were oddly quiet. He was used to living in the city, within its heart at the military complex. There was always sound and noise, life constantly moving around him. The cavern was dead atmosphere. There was the sound of small clangs, probably some debris still settling from his unorthodox entrance. Other than that it was silence, not even a draft for his sensors to pick up on. His orientation calculators had been completely thrown off in the fall.  

He had no idea on what way he actually needed to go, but to stay in this spot would do him no good. He need to figure this out on his own, and picked a direction at random.

One of his leg struts was definitely out, he decided, as he began to limp along.

 

* * *

 

He had found a tunnel, and had been traveling through it for a bit now. He had a servo against the wall, digits running over the surprisingly smooth surface to ground himself in the dark. He had turned off his headlight to conserve energy. His footsteps were the only sound his audials picked up, and there was still no hint of any kind of air current. 

The tunnel was running straight and level, and though he could take reassurance from the fact that it did not go down, he was disappointed that it was not sloping up. His leg was sore, and he tried his best to ignore that.

He didn’t notice it for a moment. A sound, and it was getting louder, getting closer to him if he was receiving the sensory information correctly. Optimus paused.

Whatever it was barrelled right into him. Thankfully, it wasn’t a wide as the tunnel, but it was still painful to be shoved against the wall by something that felt like a moving mass of armour. The creature didn’t pay attention to him, speedily shuffling along on its way as Optimus indignantly fell to the floor.

It was not his cycle.

He groaned, steadying his weight on his arms to push himself up. He shifted, moving to stand but then yelping as he crashed back to the ground. His leg strut was out for sure now, and to make matters worse he felt a piece of rock shoved in the joint.

He had been distracted first by the beast, and then his own pain. A servo shot out, gripping his neck and Optimus Prime felt fear shoot through him. From feel alone he knew it belonged to something larger than him, the claws curling around his neck cabling.

For a second he was frozen, and then he was blindly scrambling, reaching to gouge at the wrist of whatever was holding him. Whatever it was dropped him, and he gritted his dental plates to ignore the pain in his leg as he prepared to run away.

The thing was fast though. He was quickly flipped over. Jarred, he yelled as a giant pede came down on his chassis.

“You messed up my hunt.”

The words were odd… It took Optimus a moment to realize they were practically ancient. The only reason he knew them himself was for the fact that history was a hobby of his. Source material was always the best for research, and he had taken it upon himself to learn an older dialect or two to be able to understand old vids and writings.

“What?” 

The pede shifted, forcing air out of Optimus’ vents as the other loomed over him further. A servo reached out, and Optimus huffed as it grabbed his _fragging helm_. Thankfully, it just gave a swipe before moving down to feel his shoulder. “You’re a mech.”

“Yes. And you?”

The other ignored his question. “Is your kind still calling yourselves Autobots?”

Optimus hesitated, squirming underneath the uncomfortable weight. He grunted as the weight on his chest increased, the heel of the pede digging into his transformation seams. “Yes.”

“It seems your kind has somehow managed to become smaller,” there was contempt in his voice. Optimus presumed the other to be a mech, larger than he, evident by how easily he picked Optimus up after releasing him from the ground. “Why are you down here?”

“I fell.”

His optics gave off a light blue glow, and when the mech lifted him by his waist so they were faceplate to faceplate it was enough to make out the smirk on the other’s face. He imagined the face was some shade of grey without the blue tinge. The mech’s optics remained shuttered.

“I’ve managed to find myself a fool of an Autobot.”

Optimus glared, even if the other couldn’t see his expression. He didn’t bother with a reply, once again trying to make the other let go of him.

“Are you sure you really want me to drop you?” The mech didn’t really wait for a reply. “From the sound of it you were limping early. The racket you made scared off that terraslug. I don’t think you realize how much you’ve inconvenienced me by doing that.”

“The what?”

The mech moved without warning, slapping Optimus over his shoulders, and the Autobot only just managed to stop himself from calling out in pain again. “The beast that beat you into the wall. They are actually relatively harmless,” oh, the mech was definitely laughing at his expense on the inside, “we just need to eradicate them when they get too close to our complex. Their burrowing wrecks the integrity of the tunnels.

“Now, you owe me. You are most likely completely useless down here, but if you want to stay alive I’m sure you will find some way to become useful.”

 

* * *

 

The mech obviously knew where he was going. He moved along quickly, sure of his step, even gracefully enough that he wasn’t irritating Optimus’ bad strut. 

Optimus didn’t bother to keep track of the turns and twists they took; he was already disoriented down here, there would have been no point.

Soon, he could make out sound not originating from him or his companion. Footsteps, multiples sets, and slowly he was able to calibrate his sensors to be able to somewhat identify where they were coming from. The underground setting was throwing his sensors off, signals not travelling in normal patterns in the enclosed space. Rock was also not a prominent feature above the surface, and it changed the way signals bounced.

The footsteps stopped, and Optimus realized they were passing two bots. He heard them shuffle and then Optimus learned the name of who the mystery mech was.

“Lord Megatron.” A pause. “If we may ask, what is that?”

“A stray. I will deal with it.”

Those were only the first bots they passed. There were others, and Optimus was feeling oversensitized now as he listened to the mecha moving in the tunnels around him. It must have been a tight-knit network of tunnels they were travelling through now. They were turning and going up and down and the mech carrying him moved through it all with confidence. He obviously knew this layout, and must have known everyone in it.

Anybot they passed greeted Megatron. They all made sure to call him “lord”. Optimus had no idea where he was, who he was with, and felt completely in over his helm. He didn’t say anything, not wanting to bring attention to himself, but they all seemed to know that he was there. Some ignored him, a few were curious, but a lot made scathing remarks about him. They seemed to guess that he was an Autobot, and that apparently was enough to hate him.

They made remarks, but they did nothing else. Optimus felt a small relief when most sound began to fade away. Another few moments of walking, and then he was thrown again. He landed on what he would later on learn was a berth, and Megatron was back to looming over him.

“What did you hurt?”

“What’s it matter to you?”

Megatron harrumphed, and wretched his good leg. Optimus grunted. Megatron wretched the other and got the reaction he was looking for. “Now, do you want me to help you or not?”

Optimus regained control of his venting. “Please. There’s a rock in my hip joint.”

One servo steadied his waist, and Optimus tried to not over think how easily the other splayed his legs with his second servo. It was easier to ignore because of the pain that lanced through him with the movement. He was lucky Megatron had claws, for that was the only reason he could get in deep enough to knock loose the rock.

“Does it need to be reset?”

“Yes.” Megatron gave no warning. He just grabbed the leg right below the joint, jerking it so the struts fell back into alignment. There would be microfractures all over the joint, but Optimus’ self repair would be able to handle them.

"What is your name, Autobot?"

"Optimus Prime?"

"A true Prime?"

Optimus blinked in confusion. "What?"

Megatron stepped back and left it at that. Optimus had his sensors trained on him, as it was the easiest thing for him to read right now. He managed to keep track of the other as he left what must have been a room. He left the berth, feeling his way to follow Megatron.

“I’m sure you will figure out how to calibrate your sensors for the darkness and lack of optic input.” Optimus ran into something. “...Eventually. You need to be able to get around once I finally find a use for you.

“There is a couch in here. If you can manage to find it you can recharge on it.”

With some difficulty Optimus did manage to stumble his way to it. The next cycle (at least his chronometer hadn’t been affected in his fall) Optimus memorized the layout of Megatron’s living quarters. The other mech had left him, leaving a small ration of energon for him.

Each cycle he only got a small portion of energon. It was enough to live on, but he was running on the bare minimum.

Megatron was not welcoming, but he could be called cordial. He asked Optimus question after question, but answered very little of those Optimus asked in return.

He did learn some things. Mecha down here called themselves Decepticons, they hated Autobots, and Megatron was in charge of them all.

A wary feeling had Optimus halting his vocalizer when it came to Megatron’s questions. He gave the Decepticon as little information as he could. There was something going on, some history he didn’t know. It was obvious the Decepticons had a grudge against the Autobots.

He hadn’t gotten a good chance to figure out exactly what had happened between them. Megatron was holding out on that information, smirking every time he deflected the question. He knew he was frustrating Optimus.

There had been some progress for him though. As Megatron had figured, Optimus was getting his sensors optimized to compensate for the lack of visual information. To have his settings like this was better than relying on the feeble light of his lone functional headlight.   

Megatron had apparently taken notice of his newfound mobility. The mech gave him his cycle’s energon, waiting for Optimus to intake it this time before leaving.

“Time to see if you can earn your keep, Autobot.”

That was all he said before leaving the room, obviously expecting Optimus to follow. It was probably best to not keep his host waiting, and he quietly followed.

“You are currently the smallest bot I have at this network.” Optimus figured that was what they called the connected tunnels and caverns the Decepticons lived in. Megatron always used the word in situations where it could be substituted with the word “city”. “You’re lucky that your diminutive size can be useful every once in awhile.”

Like on the surface, they mined for energon crystals to refine for consumption. Megatron led him to the current mines, a couple of on-shift mecha waiting for them.

“This is the crevice we need him to look at, my Lord.”

The crevice was a small opening in the tunnel’s wall, big enough for Optimus to squeeze into but obviously too small for any of the Decepticons.

“What am I looking for?”

The Con’s EM field sent a message of distaste. The Decepticons used EM field communication far more often than what Optimus was used to. It was the substitute for facial expressions. “You’re going to have turn your optics back on for a bit, tiny. There’s obviously a vein of crystal on one side, but we need to know if there’s any deeper into the wall on the other. Don’t want to start widening the crack only to ignite a hidden deposit.”

“I’m sure you will be able to handle that.” Megatron then addressed the miner in charge. “Have someone make sure he gets back to my quarters when you’re done with him.”

The work was far harder than Optimus had been expecting. It was slow moving once he entered the crevice. He had to shuffle along and avoid hitting the vein that did run through the one side. The light flow from that vein of energon at least made if comfortable for his optics to be online again.

It had just been that one deposit. Optimus was dirty, tired, and running on almost dangerously low energon levels by the time he was done. The rations he had been receiving had been enough for when he spent the cycles doing nothing, but he would need more after a day’s work.

Megatron had energon ready for him when he returned, a full ration this time. He was also finally showed where the underground springs of solvent were. He now truly appreciated a good bath.

He ended up working with the miners the most, but any situation where his size was advantageous he would end up helping with.

Now that he was working everyone was less hostile to him. Some mecha even became curious. Their questions were easier answer than Megatron’s, but he still was careful. None had cared to enlighten him on the subject, but some seemed to think better of him when they found out about his ignorance of their past.

He found a rhythm in his cycles. He tried to avoid thinking about his home. It was not something he felt he could freely talk about, and though they allowed him to live with them he doubted the Decepticons would help him get back to the surface. He instead learned about those around him, falling slowly into their society.

He was surprised that he was still living with Megatron. Not everyone liked him, but he was sure he would be safe living on his own now. Megatron never brought it up though, so he did the same. He really didn't mind living with the other. They had good conversation when Megatron wasn't being invasive or overly prickly.

Optimus Prime had never expected something like this for his life, but he was enjoying himself.

 

* * *

 

He had finally managed to get someone to talk.

He returned from his day’s work, occupying himself around the living room until Megatron returned.

He didn’t know what to think. He wondered what the Decepticons really had done, to push his faction so far, but he also wondered what kind of justice this was, to force one half of the planet into hiding.

He felt content here, but now part of his trust in his hosts had shattered. Megatron returned and they both exploded. Optimus realized he may have been irrational, but he was angry. He felt belittled that no one would share this information with him, especially when he had first found his way here.

He had wandered into enemy territory without even knowing it. They had kept that secret at his expense. He knew now how much danger he had been in when he was first brought here.

It was a heated argument, and it derailed quickly. Optimus couldn’t say everything they had argued over. It had started with the fact that Optimus would have liked to know they were technically enemies from the get go, but they would have to wound their prides to actually admit that it had gotten petty by the end of their fight.

They had ended up in each other’s faceplates, EM fields charged with energy and flickering wildly around them. Megatron grabbed his shoulder and Optimus frowned, ignoring the giant, warm servo that was holding him.

They stayed like that for a moment, venting angrily, not saying another word. Optimus huffed, jerking his shoulder free and moving to plop down on his couch to recharge.

They didn’t talk much the next couple of cycles. They passed each other with their EM fields pulled tight, not acknowledging each other.

Optimus was in the baths when Megatron came to make amends. He had been investigating another small passage that cycle. His armour was caked in grit and metallic dust, rocks and dirt all stuck between his plating. There was a couple pools, all smaller in size, with constructed walls to give some semblance of privacy though they were all technically public.

He had just slipped into the pool when Megatron entered. The mech didn’t say anything; he just joined Optimus, the solvent lapping against Optimus as the larger bot settled.

“It is not my fault your command decides to keep history a secret from you,” Optimus was ready to defend his superiors, but Megatron continued before he got a word in, “but I should have informed you of the fact earlier. You have had my protection since I brought you here though.”

Megatron shuffled, putting his servos into the solvent, opening them so the minerals he held could dissolve into the liquid. It was a pleasant smelling cleaning agent that fizzled as it dissolved.

Optimus relaxed a little. “Why bring me here knowing I was an Autobot?”

“I was hoping to get more information about the surface from you. We may be able to survive down here, but we all long to return to the surface. Most of us are meant to fly believe it or not, and though we have managed to find some caverns large enough, it is not the same as the open sky. My people miss their home and I shall one day bring them back to it.”

Optimus Prime understood Megatron’s desire, but the mech spoke with a fire to his words that worried the younger bot. There had been distrust for him just because of the fact he was an Autobot, some had hated him for it. He worried about how much Megatron would do to return to the surface.

“But, you are smarter than you first appeared,” Megatron’s field flickered with humour. “You’ve hardly given me anything useful at all.

“We Decepticons will return to the surface one day, and I will welcome your assistance if you choose to give it. But that is talk for another night Optimus Prime,” Megatron reached over, guiding Optimus to sit on a ledge within the pool so he could reach his back plating, “this is to make up from my transgression against you.”

Though they were large and clawed, Megatron’s servos could be light and deft when he wanted them to be. He grabbed the cloth made from fine woven metal that Optimus had brought, dipping it into the solvent before he began to scrub the younger bot’s plating.

It was relaxing. The minerals tingled against the softer materials underneath his armour, and Megatron’s claws made it so he was better able to get at the grit stuck underneath it all. Optimus found himself truly relaxing and enjoying it. It was a calming, personal touch he hadn’t felt in a long time.

Optimus hummed, leaning into the touch. Megatron was thorough; the Autobot’s back plating would have shined if there had been light.

Megatron helped him with any spots that would not have been invasive, leaving Optimus to finish his grooming when that was done.

That was by far an improvement on the arguing.

 

* * *

 

They were just leaving the mines; Megatron had been checking on productions levels and Optimus had been doing his usual surveying. The first vibration had been very subtle; Optimus had almost missed it, but Megatron’s reaction had been immediate.

They stopped, waiting. Then there was a change in the atmosphere as the blastwave hit them, a gust of heat and the acrid smell of unrefined energon burning. What was the biggest worry though was the rumbling that followed.

Optimus had no idea what to do. Like the day he first met Megatron he froze. Unlike that day though, he now had a good idea what was going on, and the ability to sense his surroundings. When Megatron started to run he followed.

It was loud, disorienting. The vein that had ignited must have been running in the same direction that they had been heading in, as their tunnel still continued to crumble the farther they went.

It was sheer luck that he noticed, and he thanked Primus for his quick reaction. The rumbling had grown louder, and as his shorter stride already had him lagging behind, Optimus began to pay more and more attention to their surroundings than simply just picking up speed like Megatron did.

Two large _cracks_ and another rumble was the warning Optimus had. He improvised, and hoped he would have decent aim even though he had never done this without a visual feed before.  

His grappling hooks shot out, and he ran his legs through a partial transformation sequence, bringing his tires down to the ground. The moment he felt the hooks wrap around Megatron’s legs he reversed, the uneven floor tearing into his tires but giving himself enough force to halt Megatron’s momentum.

The Decepticon snarled, but he fell, landing on the floor in a heap. In front of him, the ceiling came down, smaller rubble pelting his helm, but he was missed by the main mass of rock and metal.

Optimus vented heavily from where he had flopped on the floor, cringing as he transformed his legs to bring his wheels back up, the torn rubber catching on the rest of his plating. He felt a tug on his grappling cables, figuring that Megatron was disentangling himself.

The rumbling died down.  They didn’t move, waiting, but all seemed to settle. Megatron finally stood, ghosting over and reaching down to help Optimus up. “Are you alright?”

The Autobot flinched as he stood on his pedes, his legs aching from his torn wheels. “Yes, I am. Are you?”

“Yes. Good, quick thinking.”

Megatron returned to the fallen ceiling, carefully running his servos over it. “This way is no use to us.” He turned, motioning Optimus to follow. “Let’s find another way.”

They wandered, carefully and slowly. After some time, they met up with a couple other mecha. They had not been at the ignition site either, but Optimus doubted they would meet anyone who knew what had exactly happened.

A usable tunnel was found, but it had been a very roundabout route to get back to the main complex. There was others waiting for them.

They were some of the last back, a few search parties still out to find the few who had yet to be found. A medic tended to his wheels, using fasteners with the hope that his self repair would mend the tires properly back together with the help. The supplements he would have to take for that were disgusting, but it could have been worse.

Megatron sent him back to their quarters. Optimus offered to help but the other still sent him off.

He got there and immediately headed for his couch. He felt exhausted, both physically and mentally as the events of the cycle caught up to him. He practically tumbled onto the couch, falling into recharge.

It was some time later when something jostled his arm.

“Come, you’re filthy.”

“I was recharging.”

“I have more bath minerals. The medic said this one would also help with your injury.”

Optimus contemplated for a moment more before moving. The truck got up gingerly, still being careful with his tires.

The pools were empty, but it was the middle of the off cycle. It was uncomfortable when Optimus first slipped into the solvent, the liquid cleaning his tires with a sting. Megatron entered, immediately putting in the minerals.

It took time for them to fully diffuse, but Optimus could soon feel the effect it had on his injuries. They were numbing the wounds, but only brought about an enjoyable tingling on other body parts like the previous mineral they had used. It interacted differently with the nonmetallic tire treads.

He hummed in contentment, beginning to clean himself. The dirt and grim of earlier slipped away, and so did his weariness. It felt marvelous. These minerals were even stronger than the last, and it felt like he could feel them over the whole of his body. He had heard of bots losing or no longer using one sense to strengthen their others, but he had spent so much time focusing on his auditory and location sensors in the last little while he hadn’t thought much of his tactile sensors. 

Optimus couldn’t help a squeak of shock when Megatron’s servos landed on his back, but he quickly relaxed again as the other began to clean him like last time. Slow, firm movements had Optimus leaning back into the other.

Megatron travelled his way down Optimus’ back, servos not hesitating when they began to dig into the sensitive seams at his hips.

Optimus squirmed, slightly, as Megatron continued to clean his plating. His hips had been one of the areas Megatron had left alone last time. He gasped when one servo reached around, blatantly rubbing against his interface panel.  

“There are admirable qualities about you. You’ve done well to survive down here Optimus Prime.” The servo moved away from his panel, but both remained to lewdly massage his thighs. “Thank you. You saved me from grievous injury if not death earlier.”

Optimus reached down, placing his servos on Megatron’s own. “Would this be a “thank you” too?”

“No, this is an exploration of an interest.”

Optimus thought, and Megatron waited. The Bot came to a decision. Curling his digits around Megatron’s servo, he slide the bigger bot’s servo back down to his interface panel.

Megatron pulled him closer to him, bringing Optimus into his lap. He was so much larger than the Autobot, a presence behind him as he leaned down to Optimus’ audile. He could feel the breath of warm air gusting over his finials as Megatron spoke. “Are you sure?”

Optimus nodded, and Megatron’s engine rumbled. The Autobot gasped, feeling every vibration as it ran through his plating, the minerals still present in the solvent adding to the sensation.

Those large servos were back on him, roaming all over his body and leaving trails of heat in their wake. There was not much of Megatron that he could reach in this position, but he moved his arms underneath Megatron’s own, finding the seams that he could reach and play with in the other’s hips and thighs.

Megatron’s engine revved again, and he began to move Optimus around.

The smaller bot didn’t want to admit how the heat in his interface grew as Megatron maneuvered him to his want. Megatron grabbed both of his legs, carefully throwing them to either side of his thighs to avoid irritating his tires, leaving the bot splayed wide over his lower body. He took Optimus’ wrists in one servo, pulling them up above his head so the whole of his body was on display.

The free servo reached down, returning to Optimus’ panel, and the Bot bucked up into it once before retracting it.

The mineral-infused solvent made his array tingle, and it wouldn’t be long before his valve would be lubricating into the liquid. Optimus didn’t bother to retract his spike panel, but the other didn’t seem to mind him making the choice in their positions. Megatron’s clawed digits began to trace the lips of Optimus’ valve.

Optimus sighed, leaning back into Megatron’s chassis. Megatron teased him, pinching the outside of his valve and his anterior node, leaving him squirming and wanting something more.

“Please.”

He felt a grin against the top of his helm. Megatron’s mouth moved, licking and nipping at Optimus’ finials, hot and wet against them and then he would leave them to be exposed to the cool air and he felt his charge going even higher. He moaned, bucking and trying to force Megatron’s digits inside him. 

Finally, other relented. One of the digits slipped inside, and the thought of those sharp claws inside him was horrible arousing. Soon, another joined, and they moved with slow, deft movements like when Megatron had been cleaning his plating. Megatron worked him open, tips rasping over nodes as the size of the digits slowly spread him wider.

Optimus was a gasping mewling mess by the time he felt a spike pressurize against his back. Immediately, he knew it was big, bigger than anything he had taken inside himself before. Well, it was a good thing his partner had been thorough, even though he had spent the last how long just on the edge of overload, but not being pushed over.

Megatron’s vents were roaring, and Optimus realized just how much the display of himself had turned the other on.  The Decepticon’s servo remained at his valve a moment longer though, digits beginning to scissor against his walls to force a stretch that was just on the side of not too much. He gasped again, and it turned into a moan as Megatron bit lightly at a finial. Those digits scissored and thrusted a couple more times, Megatron’s thumb suddenly pressing down on Optimus’ anterior node and he came with a yell, riding the servo buried in him.

Megatron quickly flipped him over to face him, practically holding the Autobot as he rode out the last sensations of the overload. Optimus was feeling so many other sensations he forgot about the ache in his calves. Megatron smirked as he lined up his spike. “We are in public. With all that noise you’re going to encourage someone to come find us.”

Optimus’ field flushed with a slight embarrassment at that. That was the thought that made him choke on his moan, whining instead as Megatron slowly pushed his spike inside of him.

Oh, it was definitely larger than anything that he had had before but it felt _amazing_. Optimus was stretching to a degree he hadn’t thought possible, and it was sinful how much he was enjoying it.

Somehow he managed to fully seat himself. Megatron paused, but it was obvious by how tense the other was that he was very much ready to frag Optimus senseless. After a moment to relax, Optimus nodded, and they both couldn’t help but groan with Megatron’s first thrust.

It was started with a slow pace, but soon they gained speed and rhythm and Optimus was grinding himself down in time with Megatron’s thrusts. He felt full, the spike rubbing against his inner nodes and grazing the deepest parts of his valve. He was clamping down on his vocalizer, mewling and whining to avoid the loud moans and sighs he wanted to make.

Megatron grunted, pulling him closer, bending down to tease his finials for the height difference made kissing too awkward.

The sounds Megatron made were quiet, the most prominent being the rumbling of his engines. With the way his sensors were Optimus still managed to take in it all. He could hear every gasp the Decepticon made against his helm. He squeezed his valve walls and heard the falter in Megatron’s venting. He heard the constant rumble of the other’s engine and felt every rev against his plating. With each thrust the solvent lapped around them, and Optimus felt almost oversensitized, and yet that was just making him concentrate of that feeling of that spike in his valve even more.   

Neither of them would last much longer. Their EM fields crackled with arousal, and Optimus felt like he was close of overheating in the warm solvent. Megatron’s servos gripped his hips, squeezing as he began to thrust harder.

Optimus did moan this time. Megatron's spike was slamming into his ceiling node, once, twice, and then he came, vocalizer shorting out with his yell. He rode out the overload, rolling and grinding his hips as Megatron finished inside him.

Optimus was now exhausted again. He hummed, snuggling up into the other’s chassis just a for a klik. Megatron’s arms curled around him.

There was much Optimus Prime was uncertain about in life. He was far from home, learning how to live with those who were technically his enemy. Right now he was content to stay right here for a little bit longer though.

 


End file.
